In general, your cell service must still be active to keep the same number when switching to a different provider.
If by "update" you mean change the SIM card number that is currently active with your cellphone provider, then either a) Call the international number for your provider and ask them to switch it. ; or b) Log in to the online Self Service your provider may have and switch it there.
samsung gt-c3312
You cannot change the fax number. It is provided by a telephone company or fax service provider and you can't edit it. Call your fax service provider to change you fax number.
I'm assuming the phones are on different networks. You would contact the service provider of the old phone and tell them you want to 'migrate' the number to a different network. You are asking for the 'Port Authorisation Code' (PAC) - they should give you this for free. You give the PAC to the new provider and they'll do the change for you.
The new iPhones come with a SIM lock which means it is not possible to change the service provider of the phones. There are grey markets vendors who might help you break the SIM lock and use the iPhone for other service providers. But remember, your iPhone warranty will become invalid if you do that. With the mobile phone portability service available you can change your cell phone service providers and still retain your old phone number.
You can contact your service provider and ask them to change it.
demarcation point
demarcation point
The ONLY way - is to contact your service provider - they are the only people who can supply you with the code for your handset (every one is different)
You would need to contact your service provider - and ask them for a new number.
On your last oil-change service, the service center should have stuck a sticker on your windshield that tells you at what mileage is your next oil change.
While Verizon does offer service for the iPhone 4, if you are transferring from another service provider, you will need to change phones with one from Verizon.